A variety of delivery systems are known that deliver gas at positive pressure for consumption by the user. The uses and applications of such systems vary. Some such systems have been developed for the treatment of sleep apnea.
Sleep apnea syndrome is an episodic upper airway obstruction during sleep. As a consequence, there is repeated interruption of sleep in the patient. Positive airway pressure (PAP) devices have been developed to treat this disorder. A typical PAP device comprises a flow generator (e.g., a blower) which delivers gas via a delivery conduit to a patient interface, such as a mask.
Several types of respiratory face masks for delivering gas to a patient are known. One such mask incorporates ports in the body of the mask to provide an exhaust leak to purge the system of CO.sub.2 laden air. However, several drawbacks are associated with ports in the body of the mask. For example, air exiting the mask ports may create noise or blow on the patient, causing discomfort.
Respironics, Inc. of Murrysville, Pa. has developed and manufactured a swivel conduit having exhaust vents under the name Whisper Swivel.RTM. Exhalation Port see FIG. 1a. This two-piece swivel conduit not only provides a swivel connection between the mask and the delivery conduit but also includes a plurality of downwardly directed exhaust slits. The slit configuration of the vents acts to reduce noise and direct the CO.sub.2 laden exhaust away from the patient.